Electronic Telegram No. 4012
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


(2623) ZECH
      D. Pray, Sugarloaf Mountain Observatory, South Deerfield, MA, U.S.A.;
P. Pravec, Ondrejov Observatory; V. Chiorny and Yu. N. Krugly, Kharkiv
Observatory; V. Benishek, Belgrade Observatory; J. Pollock, D. B. Caton, A. B.
Smith, and R. L. Hawkins, Appalachian State University; R. Inasaridze,
Abastumani Observatory; R. Montaigut and A. Leroy, OPERA Observatory, France;
and D. E. Reichart, J. B. Haislip and A. P. LaCluyze, University of North
Carolina, Chapel Hill, report that photometric observations obtained during
2014 Oct. 7-31 reveal that minor planet (2623) is a binary system with an
orbital period of 117.2 +/- 0.3 hr.  The primary shows a period of 2.7401 +/-
0.0002 hr, and it has a lightcurve amplitude of 0.22 mag at solar phases
13-25 deg, suggesting a nearly spheroidal shape.  Mutual eclipse/occultation
events that are 0.09-magnitude deep indicate a lower limit on the
secondary-to-primary mean-diameter ratio of 0.29.  The secondary is
non-synchronous, and it has a period of 18.718 +/- 0.008 hr and an amplitude
of 0.08 mag in the observed lightcurve, suggesting a secondary elongation of
about 2:1 after removing contribution of light from the primary.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 November 5                  (CBET 4012)              Daniel W. E. Green